Roller guide shoes or sliding guides connected to a door panel are used in the prior-art sliding doors of an elevator or of automatic doors for guiding the door panel, which guide shoes or sliding guides guide closely following a guide rail by taking support force that is lateral with respect to the direction of movement of the guide from the guide rail. The guides are generally disposed on the top edge and/or on the bottom edge of the door panel. The guide rails are generally disposed in the floor of the building or corresponding or in the door header of the door opening.
The type of sliding doors with sliding guides, in which support force is taken from a guide rail with only a sliding guide that moves in a guiding groove, are known in the art. Sliding parts, however, wear quickly and a problem therefore is rapid impairment of the quality, e.g. the evenness, of the slide.
Also known in the art are the type of sliding doors with roller guide shoes, in which the roll of the guide is between two guide rail surfaces, guided by both of which the roll in question is arranged to guide the sliding door supported on the guide rail surface of that side, to which the roll is closest at the time. This type of solution is presented in, among others, publication JP2002308556A. One problem with these types of solutions is the continuously repeated change of rotation direction of the roll, which change always occurs when the roll swings in the lateral direction from the guidance of a first guide rail surface to a second. This increases the wearing of the surface and bearing of the roll and at its worst might cause noise. It is advantageous to dimension the roll to travel close to both guide rail surfaces. A problem in this case is also that, e.g. as a result of becoming dirty, the roll is not necessarily able to rotate freely and starts to slide against the surfaces of the guide rail, thus being in contact with the surface of two guides at the same time, which might increase the wearing.
A problem in all these solutions is that as the primary guide element (roll or sliding shoe) of a guide wears, its dimensions change so that the clearances of the guide increase to be such that the sliding door no longer travels evenly and might produce noise. After the occurrence of this wearing problem, the sliding guide part must be replaced very quickly, because the sliding guide quickly loses its usability completely.